1 .. -*- coding: utf-8; mode: rst -*-
5 ********************************
6 ioctl VIDIOC_G_STD, VIDIOC_S_STD
7 ********************************
12 Query or select the video standard of the current input
18 .. c:function:: int ioctl( int fd, int request, v4l2_std_id *argp )
20 .. c:function:: int ioctl( int fd, int request, const v4l2_std_id *argp )
26 File descriptor returned by :ref:`open() <func-open>`.
29 VIDIOC_G_STD, VIDIOC_S_STD
37 To query and select the current video standard applications use the
38 ``VIDIOC_G_STD`` and ``VIDIOC_S_STD`` ioctls which take a pointer to a
39 :ref:`v4l2_std_id <v4l2-std-id>` type as argument. ``VIDIOC_G_STD``
40 can return a single flag or a set of flags as in struct
41 :ref:`v4l2_standard <v4l2-standard>` field ``id``. The flags must be
42 unambiguous such that they appear in only one enumerated
43 :c:type:`struct v4l2_standard` structure.
45 ``VIDIOC_S_STD`` accepts one or more flags, being a write-only ioctl it
46 does not return the actual new standard as ``VIDIOC_G_STD`` does. When
47 no flags are given or the current input does not support the requested
48 standard the driver returns an EINVAL error code. When the standard set
49 is ambiguous drivers may return EINVAL or choose any of the requested
50 standards. If the current input or output does not support standard
51 video timings (e.g. if :ref:`VIDIOC_ENUMINPUT <vidioc-enuminput>`
52 does not set the ``V4L2_IN_CAP_STD`` flag), then ENODATA error code is
59 On success 0 is returned, on error -1 and the ``errno`` variable is set
60 appropriately. The generic error codes are described at the
61 :ref:`Generic Error Codes <gen-errors>` chapter.
64 The ``VIDIOC_S_STD`` parameter was unsuitable.
67 Standard video timings are not supported for this input or output.
70 .. ------------------------------------------------------------------------------
71 .. This file was automatically converted from DocBook-XML with the dbxml
72 .. library (https://github.com/return42/sphkerneldoc). The origin XML comes
73 .. from the linux kernel, refer to:
75 .. * https://github.com/torvalds/linux/tree/master/Documentation/DocBook
76 .. ------------------------------------------------------------------------------